Because the Church is going to put together a set of letters written to communities here and there...declare them as inspired...while knowing that this set of letters will contradict the whole of catholic teaching that had developed in the prior 350 years. Then they will be the only people available that could read and write...painstakingly preserving said inspired letters...all the while worshiping in a manner that is completely contradicted by the letters that they are preserving ...yep makes sense to me
Peter already called Paul's letters "scripture". The oracles of God were entrusted to the Jews and NOT to the Catholic Church. Then read the article for more of your answer.